i am working on hyster gm v6 vortec.the transmission return to neutral when ever the lever is pull forward. i have inspected the transmission harness,replaced the vsm ,control valve and solenoid attached,flushed the sump but the problem still persist.it is an lpg system with fault 524225-1 which means transducers and that has been replaced too.the gear doesn't engaged.can somebody help me because am **** off.